Surface-emitting type semiconductor laser and method for manufacturing the same

ABSTRACT

To provide surface-emitting type semiconductor lasers and methods of manufacturing the same in which the polarization direction of laser light can be readily controlled, a surface-emitting type semiconductor laser includes a vertical resonator above a substrate. The vertical resonator includes a first mirror, an active layer and a second mirror disposed in this order from the substrate. The vertical resonator has a plurality of unit resonators. An emission region of each of the unit resonators has a diameter that oscillates in a single-mode.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to Japanese Patent ApplicationNo. 2003-326296 filed Sep. 18, 2003 which is hereby expresslyincorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of Invention

Exemplary aspects of present invention relate to surface-emitting typesemiconductor lasers and methods for manufacturing the same.

2. Description of Related Art

A surface emitting semiconductor laser is a semiconductor laser whichemits laser light in a direction perpendicular to a semiconductorsubstrate. Since surface emitting type semiconductor lasers haveexcellent characteristics including, for example, easy handling, lowthreshold currents, etc., compared to related art edge emittingsemiconductor lasers, application of surface emitting type semiconductorlasers to a variety of sensors and light sources for opticalcommunications are expected. However, the control of polarization planesof a surface-emitting type semiconductor laser is difficult because ofthe symmetry of its planar structure. Therefore, when a surface-emittingtype semiconductor laser is used for an optical system with apolarization dependence, instability of polarization planes causesnoise. In this respect, a variety of related art methods to controlpolarization planes are discussed below.

Japanese laid-open patent application HEI 5-67838 discloses a method tocontrol polarization planes by providing a diffraction grating within aresonator. In this case, only specific polarization remains within theresonator, and only a mode having the polarization oscillates. However,its manufacturing method is complex and therefore stable manufacture maybe difficult.

Japanese laid-open patent application HEI 6-53599 discloses a method tocontrol polarization planes by forming quantum fine wires in an activelayer. In this case, the quantum fine wire structure exhibits strongpolarization characteristic because quantum confinement exists in itsin-plane direction. However, its manufacturing method is complex, andtherefore stable manufacture may be difficult.

Japanese laid-open patent application HEI 10-209566 discloses a methodto control polarization planes by providing a control electrode. In thiscase, by injecting an electrical current into the control electrode, theoscillation mode and polarization of laser light can be controlled, andthe beam profile can also be adjusted. However, according to thismethod, a power supply source for control is required, and the powerconsumption may increase.

SUMMARY OF THE INVENTION

Exemplary aspects of the present invention provide surface-emitting typesemiconductor lasers and methods for manufacturing the same, which canreadily control polarization directions of laser light.

A surface-emitting type semiconductor laser in accordance with anexemplary aspect of the present invention pertains to a surface-emittingtype semiconductor laser having a vertical resonator above a substrate.The vertical resonator includes a first mirror, an active layer and asecond mirror disposed in this order from the side of the substrate, andthe vertical resonator has a plurality of unit resonators. An emissionregion of each of the unit resonators has a diameter that oscillates ina single-mode.

According to the surface-emitting type semiconductor laser, either insingle-mode oscillation or multimode oscillation of laser light, theemission pattern can be formed into an optional shape by controlling theplanar configuration, number and arrangement of emission regions of theunit resonators. For this reason, exemplary aspects of the presentinvention can be employed in light sources of laser printers, sensorsand the like.

In a surface-emitting type semiconductor laser in accordance with anexemplary aspect of the present invention, the vertical resonator caninclude a unit current aperture layer formed along at least a part of acircumference of each of the unit resonators, and the diameter of theemission region can be defined by an opening section of the unit currentaperture layer.

In a surface-emitting type semiconductor laser in accordance with anexemplary aspect of the present invention, the respective unitresonators can be continuous, and a planar configuration of the verticalresonator can have anisotropy.

The planer configuration having anisotropy means that there are a majoraxis and a minor axis that intersect at right angles through the centerof the planar configuration. In this instance, it is assumed thatanisotropy is present in the direction of the major axis.

According to this surface-emitting type semiconductor laser, each of theunit resonators oscillates in a single-mode, and thus its polarizationdirection is in one direction. When these unit resonators are continuousand the vertical resonator has an anisotripic planar configuration, thepolarization directions of laser light of the unit resonators can bealigned according to the anisotropy in the planar configuration of thevertical resonator. For this reason, according to the presentsurface-emitting type semiconductor laser, the polarization direction oflaser light to be emitted can be controlled.

In a surface-emitting type semiconductor laser in accordance with anexemplary aspect of the present invention, the respective unitresonators can be continuous through a continuation region.

In a surface-emitting type semiconductor laser in accordance with anexemplary aspect of the present invention, a planar configuration ofeach of the unit resonators can have anisotropy.

According to the surface-emitting type semiconductor laser, each of theunit resonators oscillates in a single-mode, and thus its polarizationdirection is in one direction. Because the planar configuration of eachof the unit resonators has anisotropy, polarization directions of laserlight of the unit resonators can be aligned according to the anisotropyof the planar configuration of each of the unit resonators. For thisreason, the polarization direction of laser light to be emitted isaligned. Specifically, according to the present surface-emitting typesemiconductor laser, the polarization direction of laser light to beemitted can be controlled.

In a surface-emitting type semiconductor laser in accordance with anexemplary aspect of the present invention, each of the unit resonatorscan have the same diameter, and laser light of each of the unitresonators can have the same wavelength.

In a surface-emitting type semiconductor laser in accordance with anexemplary aspect of the present invention, the unit resonators can haveat least two different diameters, and laser light generated by the unitresonators can have at least two different wavelengths.

In a surface-emitting type semiconductor laser in accordance with anexemplary aspect of the present invention, the vertical resonator canhave an aperture section that reaches at least the unit current aperturelayer.

In a surface-emitting type semiconductor laser in accordance with anexemplary aspect of the present invention, the aperture section can beembedded with insulation material.

A method for manufacturing a surface-emitting type semiconductor laserin accordance with an exemplary aspect of the present invention pertainsto a method for manufacturing a surface-emitting type semiconductorlaser having a vertical resonator above a substrate, and includes:stacking semiconductor layers to form at least a first mirror, an activelayer and a second mirror over the substrate; and forming a verticalresonator having a columnar section by etching the semiconductor layersby using a mask layer. The vertical resonator is formed to have aplurality of unit resonators, and an emission region of each of the unitresonators is formed to have a diameter that oscillates in asingle-mode.

The method for manufacturing a surface-emitting type semiconductor laserin accordance with an exemplary aspect of the present invention mayfurther include forming a unit current aperture layer along at least apart of a circumference of the unit resonators.

A method for manufacturing a surface-emitting type semiconductor laserin accordance with an exemplary aspect of the present invention pertainsto a method for manufacturing a surface-emitting type semiconductorlaser having a vertical resonator above a substrate, and includes:stacking semiconductor layers to form at least a first mirror, an activelayer and a second mirror over the substrate; forming aperture sectionsby etching the semiconductor layers; and forming current aperture layersnear the active layer by oxidizing a part of the semiconductor layersthrough the aperture sections. The vertical resonator is formed to havea plurality of unit resonators. An emission region of each of the unitresonators is formed to have a diameter that oscillates in asingle-mode, and the current aperture layer is formed along at least apart of a circumference of each of the unit resonators.

In the method for manufacturing a surface-emitting type semiconductorlaser in accordance with an exemplary aspect of the present invention,the aperture sections can be disposed at intersections of longitudinaland transverse lines composing a lattice shape, and longitudinal andtransverse pitch widths of the lattice shape can be different from oneanother.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of a surface-emitting type semiconductor laser inaccordance with a first exemplary embodiment of the present invention;

FIG. 2 is a schematic of a portion of the surface-emitting typesemiconductor laser of the first exemplary embodiment;

FIG. 3 is a schematic of a portion of the surface-emitting typesemiconductor laser of the first exemplary embodiment;

FIG. 4 is a schematic of a portion of the surface-emitting typesemiconductor laser of the first exemplary embodiment;

FIG. 5 is a schematic of a portion of the surface-emitting typesemiconductor laser of the first exemplary embodiment;

FIG. 6 is a schematic of a surface-emitting type semiconductor laserrelating to the first exemplary embodiment of the present invention;

FIG. 7 is a schematic showing a step of manufacturing thesurface-emitting type semiconductor laser in accordance with the firstexemplary embodiment;

FIG. 8 is a schematic showing a step of manufacturing thesurface-emitting type semiconductor laser in accordance with the firstexemplary embodiment.

FIG. 9 is a schematic showing a step of manufacturing thesurface-emitting type semiconductor laser in accordance with the firstexemplary embodiment;

FIG. 10 is a schematic showing a step of manufacturing thesurface-emitting type semiconductor laser in accordance with the firstexemplary embodiment.

FIG. 11 is a schematic of a surface-emitting type semiconductor laser inaccordance with a second exemplary embodiment of the present invention;

FIG. 12 is a cross-sectional schematic taken along plane A-A of thesurface-emitting type semiconductor laser of the second exemplaryembodiment shown in FIG. 11;

FIG. 13 is a cross-sectional schematic taken along plane B-B of thesurface-emitting type semiconductor laser of the second exemplaryembodiment shown in FIG. 11;

FIG. 14 is a cross-sectional schematic taken along plane C-C of thesurface-emitting type semiconductor laser of the second exemplaryembodiment shown in FIG. 11;

FIG. 15 schematic of a portion of the surface-emitting typesemiconductor laser of the second exemplary embodiment;

FIG. 16 is a schematic of the surface-emitting type semiconductor laserof the second exemplary embodiment;

FIG. 17 is a schematic showing a step of manufacturing thesurface-emitting type semiconductor laser in accordance with the secondexemplary embodiment;

FIG. 18 is a schematic showing a step of manufacturing thesurface-emitting type semiconductor laser in accordance with the secondexemplary embodiment;

FIG. 19 is a schematic showing a step of manufacturing thesurface-emitting type semiconductor laser in accordance with the secondexemplary embodiment;

FIG. 20 is a schematic showing a step of manufacturing thesurface-emitting type semiconductor laser in accordance with the secondexemplary embodiment;

FIG. 21 is a schematic showing a step of manufacturing thesurface-emitting type semiconductor laser in accordance with the secondexemplary embodiment;

FIG. 22 is a schematic showing a step of manufacturing thesurface-emitting type semiconductor laser in accordance with the secondexemplary embodiment;

FIG. 23 is a schematic showing a step of manufacturing thesurface-emitting type semiconductor laser in accordance with the secondexemplary embodiment; and

FIG. 24 is a schematic showing a step of manufacturing thesurface-emitting type semiconductor laser in accordance with the secondexemplary embodiment.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary embodiments of the present invention are described below withreference to the accompanying drawings.

1. First Exemplary Embodiment

1-1. Device Structure

FIG. 1 is a schematic of a surface-emitting type semiconductor laser(hereinafter “surface emitting laser”) 100 in accordance with a firstexemplary embodiment of the present invention. FIG. 2-FIG. 5schematically show plan views of major portions of the surface-emittinglaser 100 of the first exemplary embodiment.

The surface emitting laser 100 according to the present exemplaryembodiment shown in FIG. 1 includes a semiconductor substrate (a GaAssubstrate in the present exemplary embodiment) 101, a vertical resonator140 formed on the semiconductor substrate 101, a first electrode 107 anda second electrode 109. The vertical resonator 140 includes a firstmirror 102, an active layer 103, and a second mirror 104.

Next, components of the surface-emitting laser 100 are described below.

The vertical resonator 140 may be formed, for example, from the firstmirror 102 that is a distributed reflection type multilayer mirror of 40pairs of alternately laminated n-type Al_(0.9)Ga_(0.1)As layers andn-type Al_(01.5)Ga_(0.85)As layers, the active layer 103 composed ofGaAs well layers and Al_(0.3 Ga) _(0.7)As barrier layers in which thewell layers include a quantum well structure composed of three layers,and the second mirror 104 that is a distributed reflection typemultilayer mirror of 25 pairs of alternately laminated p-typeAl_(0.9)Ga_(0.1)As layers and p-type Al_(0.15) Ga_(0.85)As layers, whichare successively stacked in layers. It is noted that the composition ofeach of the layers and the number of the layers forming the first mirror102, the active layer 103 and the second mirror 104 are not limited tothe above.

The second mirror 104 is made to be p-type, for example, by doping C, Znor Mg, and the first mirror 102 is made to be n-type, for example, bydoping Si or Se. Accordingly, the second mirror 104, the active layer103 in which no impurity is doped, and the first mirror 102 form a pindiode.

In accordance with the present exemplary embodiment, the verticalresonator 140 includes a semiconductor deposited body in a pillar shape(hereafter “first columnar section”) 130, and the side surface of thecolumnar section 130 is covered with an insulation layer 106. Thecolumnar section 130 refers to a part of the vertical resonator 140, anda semiconductor deposited body in a columnar shape including at leastthe second mirror 104.

The planar configuration of the vertical resonator 140 has anisotropy.The planer configuration having anisotropy means that there are a majoraxis and a minor axis that intersect at right angles through the centerof the planar configuration. In this instance, it is assumed thatanisotropy is present in the direction of the major axis. This similarlyapplies to exemplary embodiments to be described below. Specifically,the planer configuration having anisotropy may be a configuration, forexample, as shown in FIG. 1, where a plurality (two in the example shownin FIG. 1) of circles are connected with one another with parts thereofbeing overlapped, or the like.

The vertical resonator 140 has a plurality (two in the example shown inFIG. 1) of unit resonators 10 and 12. Each of the unit resonators 10 and12 functions as an independent resonator. Specifically, each of the unitresonators 10 and 12 can emit its own inherent laser light.

Specifically, as shown in FIG. 2, the vertical resonator 140 is formedfrom a first unit resonator 10 and a second unit resonator 12. The twounit resonators 10 and 12 are directly continued with one another. Whenviewed in an X-Y plane, the two circular unit resonators 10 and 12 haveportions overlapping with one another. The vertical resonator 140 hasanisotropy. In the example of FIG. 2, the vertical resonator 140 hasanisotropy in the X-axis direction.

A first unit current aperture layer 20 is formed in a region near theactive layer 103 among layers composing the first unit resonator 10. Asecond unit current aperture layer 22 is formed in a region near theactive layer 103 among layers composing the second unit resonator 20.The first and second unit current aperture layers 20 and 22 have a crosssection, when cut in a plane parallel with the X-Y plane in FIG. 1, inthe shape that conforms to the circumference of the columnar section130. In other words, the first unit current aperture layer 20 has an X-Ycross section in the shape that conforms to a part of the circumferenceof the first unit resonator 10. The second unit current aperture layer22 has an X-Y cross section in the shape that conforms to a part of thecircumference of the second unit resonator 12. In the example shown inFIG. 1, the planar configuration of each of the first and second unitcurrent aperture layers 20 and 22 is generally a circular ring shapewith a section thereof being cut. These ring shapes are continuous withone another at their partially cut sections. The first and second unitcurrent aperture layers 20 and 22 have opening sections 20 a and 22 a,respectively. The first and second unit current aperture layers 20 and22 may be composed of aluminum oxide, for example.

Each of emission regions 10 a and 12 a of the respective unit resonators10 and 12 has a diameter that oscillates in a single-mode. The diametersof the respective emission regions 10 a and 12 a are determined by theopening sections 20 a and 22 a of the respective unit current aperturelayers 20 and 22. This similarly applies to exemplary embodiments to bedescribed below. For example, in the example shown in FIG. 2, thediameter of the emission region 10 a of the first unit resonator 10corresponds to the diameter of the circular opening section 20 a of thefirst unit current aperture layer 20, and the diameter of the emissionregion 12 a of the second unit resonator 12 corresponds to the diameterof the circular opening section 22 a of the second unit current aperturelayer 22. The diameter that oscillates in a single-mode is appropriatelydecided depending on the position and thickness of each of the unitcurrent aperture layers 20 and 22, and wavelength, and may be, forexample, 4-4 m or less.

In the surface-emitting laser 100 in accordance with the presentexemplary embodiment, the insulation layer 106 is formed to cover sidesurfaces of the second mirror 104, the active layer 103 and the firstmirror 102, and the upper surface of the first mirror 102. For example,polyimide resin, fluorine resin, acrylic resin, epoxy resin, etc. can beused as the resin that composes the embedding insulating layer 106. Inparticular, the resin may be polyimide resin or fluorine resin in viewof their easiness of processing and nonconductivity.

A first electrode 107 is formed on the columnar section 130 and theinsulation layer 106. Furthermore, a part where the first electrode 107is not formed (an opening section) is provided in the central area ofthe upper surface of the columnar section 130. This part defines anemission region of laser light. The first electrode 107 includes amultilayer film of Au and an alloy of Au and Zn, for example. Further, asecond electrode 109 is formed on the lower surface of the semiconductorsubstrate 101. The second electrode 109 includes a multilayer film of Auand an alloy of Au of Ge, for example. In the surface-emitting laser 100shown in FIG. 1, on the columnar section 130, the first electrode 107connects to the second mirror 104, and the second electrode 109 connectsto the first mirror 102 through the semiconductor substrate 101. Anelectric current is injected into the active layer 103 by the firstelectrode 107 and the second electrode 109.

The materials to form the first and second electrodes 107 and 109 arenot limited to those described above, and, for example, metals, such asCr, Ti, Ni, Au or Pt and these alloys, etc. can be used depending on therequirements for adhesion enforcement, diffusion prevention oranti-oxidation, etc.

In the example shown in FIG. 1 and FIG. 2, the vertical resonator 140has two unit resonators 10 and 12. However, the vertical resonator 140can have a plurality of unit resonators. For example, as shown in FIG.3, the vertical resonator 140 can have five unit resonators 10, 12, 14,16 and 18. In the example in FIG. 3, three of the unit resonators 10, 12and 14 are continuous in the X-direction, and three of the unitresonators 10, 16 and 18 are continuous in the Y-direction, such thatthe vertical resonator 140 has anisotropy in two directions,specifically, the X-direction and the Y-direction.

Also, in the example shown in FIG. 1 and FIG. 2, the diameter of theemission region 10 a of the first unit resonator 10 and the diameter ofthe emission region 12 a of the second unit resonator 12 have the samelength. However, for example, as shown in FIG. 4, the diameter of theemission region 10 a of the first unit resonator 10 and the diameter ofthe emission region 12 a of the second unit resonator 12 can havedifferent lengths. When the diameter of the emission regions 10 a and 12a has the same length, laser light that is emitted from each of theemission regions 10 a and 12 a has the same wavelength. However, whenthe diameters of the emission regions 10 a and 12 a have differentlengths, laser light that is emitted from the respective emissionregions 10 a and 12 a have different wavelengths. In other words, in theexample shown in FIG. 4, the diameter of each of the emission regions 10a and 12 a is set such that the wavelengths of laser light emitted fromthe respective emission regions 10 a and 12 a are different from oneanother. The reason why the wavelength of emitted laser light isdifferent depending on the diameter of each emission region is that theelectric resistance differs depending on the diameter (larger orsmaller) of the emission region. Specifically, because the smaller thediameter of the emission region, the greater the electric resistance andthe greater the heat generated therefrom, compared to an emission regionhaving a larger diameter, the laser light shifts to the long-wavelengthside, and the two emit laser light having different wavelengths.

Moreover, in the example in FIG. 1 and FIG. 2, the first unit resonator10 and the second unit resonator 12 are directly made continuous.However, for instance, the first unit resonator 10 and the second unitresonator 12 may be made continuous through a continuation region 14, asshown in FIG. 5.

Also, in the example described with respect to FIG. 1, the unitresonators 10 and 12 have the unit current aperture layers 20 and 22,respectively. However, as shown in FIG. 6, the unit resonators 10 and 12can be formed without any unit current aperture layers. In this case,the diameter of each of the emission regions 10 a and 12 a of the unitresonators 10 and 12 is defined by the external configuration of each ofthe respective unit resonators 10 and 12.

1-2 Operation of Device

General operations of the surface-emitting type semiconductor laser 100of the present exemplary embodiment are described below. It is notedthat the following method for driving the surface-emitting typesemiconductor laser 100 is described as an example, and various changescan be made without departing from the subject matter of the presentinvention.

When applying a voltage in a forward direction to the pin diode acrossthe first electrode 107 and the second electrode 109, recombination ofelectrons and holes occur in the active layer 103, thereby causingemission of light due to the recombination. Stimulated emission occursduring the period the generated light reciprocates between the secondmirror 104 and the first mirror 102, whereby the light intensity isamplified. When the optical gain exceeds the optical loss, laseroscillation occurs, whereby laser light is emitted from the emissionsurface 108 that is present on the upper surface of the second columnarsection 130 in a direction perpendicular (in the Z-direction indicatedin FIG. 1) to the semiconductor substrate 101. It is noted here that the“direction perpendicular to the semiconductor substrate 101” correspondsto a direction perpendicular (Z-direction in FIG. 1) to a surface 101 a(a plane parallel with the X-Y plane in FIG. 1) of the semiconductorsubstrate 101.

In the surface-emitting type semiconductor laser 100 of the presentexemplary embodiment, the vertical resonator 140 has a plurality of unitresonators 10 and 12, and each of the emission regions 10 a and 12 a ofthe respective unit resonators 10 and 12 has a diameter that oscillatesin a single-mode. Further, the unit resonators 10 and 12 are continuouswith one another, and the planar configuration of the vertical resonator140 has anisotropy. Each of the unit resonators 10 and 12 causes laseroscillation in a single-mode, and therefore its polarization directionis in one direction. Due to the fact that the unit resonators 10 and 12are continuous, and the planar configuration of the vertical resonator140 has anisotropy, the polarization directions of the unit resonators10 and 12 can be aligned according to the anisotropy of the planarconfiguration of the vertical resonator 140. For this reason, thepolarization directions of laser light emitted are aligned.Specifically, laser light is emitted with its polarization directioncontrolled. More specifically, the polarization directions are alignedin the minor axis direction; for example, in the example shown in FIG.1, the polarization directions are aligned in the Y-direction.

In the surface-emitting type semiconductor laser 100 in accordance withthe present exemplary embodiment, as shown in FIG. 2, FIG. 3 or FIG. 5,when the unit resonators 10 and 12 have the same diameter, laser lightgenerated by the unit resonators 10 and 12 have the same wavelength,resulting in oscillation in a single-mode as a whole. When the unitresonators 10 and 12 have different diameters, as shown in FIG. 4, laserlight generated by the respective unit resonators 10 and 12 havedifferent wavelengths, resulting in oscillation in a multimode as awhole.

1-3 Device Manufacturing Method

Next, an example of a method of manufacturing the surface-emitting typesemiconductor laser 100 in accordance with a first exemplary embodimentof the present invention will be described with reference to FIG. 7 toFIG. 10. FIG. 7 to FIG. 10 are schematics showing the method ofmanufacturing the surface-emitting type semiconductor laser 100according to the present exemplary embodiment shown in FIG. 1, each ofwhich corresponds to the cross section shown in FIG. 1.

(1) First, on the surface of the semiconductor substrate 101 composed ofn-type GaAs, a semiconductor multilayer film 150, shown in FIG. 7, isformed by epitaxial growth while modifying its composition. It is notedhere that the semiconductor multilayer film 150 is formed from, forexample, a first mirror 102 of 40 pairs of alternately laminated n-typeAl_(0.9)Ga_(0.1)As layers and n-type Al_(0.15)Ga_(0.85)As layers, anactive layer 103 composed of GaAs well layers and Al_(0.3)Ga_(0.7)Asbarrier layers in which the well layers include a quantum well structurecomposed of three layers, and a second mirror 104 of 25 pairs ofalternately laminated p-type Al_(0.9)Ga_(0.1)As layers and p-typeAl_(0.15)Ga_(0.85)As layers. These layers are successively stacked inlayers on the semiconductor substrate 101 to thereby form thesemiconductor multilayer film 150.

When growing the second mirror 104, at least one layer thereof adjacentto the active layer 103 is formed as an AlAs layer or an AlGaAs layerthat is later oxidized and becomes current aperture layers 20 and 22(see FIG. 1). Also, the uppermost surface layer of the second mirror 104may preferably be formed to have a high carrier density such that ohmcontact can be readily made with an electrode (first electrode 107).

The temperature at which the epitaxial growth is conducted isappropriately decided depending on the growth method, the kind of rawmaterial, the type of the semiconductor substrate 101, and the kind,thickness and carrier density of the semiconductor multilayer film 150to be formed, and in general may be 450° C.-800° C. Also, the timerequired for conducting the epitaxial growth is appropriately decidedlike the temperature. Also, a metal-organic chemical vapor deposition(MOVPE: Metal-Organic Vapor Phase Epitaxy) method, a MBE method(Molecular Beam Epitaxy) method or a LPE (Liquid Phase Epitaxy) methodcan be used as a method for the epitaxial growth.

Next, resist is coated on the semiconductor multilayer film 150. Thenthe resist is patterned by a photolithography method, thereby forming afirst mask layer R100 having a specified pattern, as shown in FIG. 7.The first mask layer R100 is formed above an area where a columnarsection 130 (see FIG. 1) is to be formed. The first mask layer R100 isformed in a manner that its planar configuration has anisotropy. As aresult, the columnar section 130 is formed such that its planarconfiguration has anisotropy. Next, by using the first mask layer R100as a mask, the second mirror 104, the active layer 103, and a part ofthe first mirror 102 are etched by, for example, a dry etching method,thereby forming a columnar section 130, as shown in FIG. 8. Then, thefirst mask layer R100 is removed.

By the steps described above, a vertical resonator 140 including thecolumnar section 130 is formed on the semiconductor substrate 101, asshown in FIG. 8.

Next, by placing the semiconductor substrate 101 on which the verticalresonator 140 is formed through the aforementioned steps in a watervapor atmosphere at about 400° C., for example, the layer having a highAl composition (a layer with an Al composition being 0.95 or higher)provided in the second mirror 104 is oxidized from its side surface,thereby forming the current aperture layers 20 and 22. The oxidationrate depends on the temperature of the furnace, the amount of watervapor supply, and the Al composition and the film thickness of the layerto be oxidized.

By the steps described above, a portion that functions as a lightemitting element (excluding first and second electrodes 107 and 109) inthe surface-emitting laser 100 is formed.

(2) Next, an embedding insulation layer 106 that surrounds a part of thefirst mirror 102, the active layer 103 and the second mirror 104 isformed (see FIG. 1).

Here, the case in which polyimide resin is used as a material to formthe embedding insulation layer 106 will be described. First, a resinprecursor (polyimide precursor) is coated on the vertical resonator 140by using, for example, a spin coat method, to thereby form a resinprecursor layer. In this instance, the resin precursor layer is formedsuch that its film thickness is greater than the height of the columnarsection 130. As the method of forming the resin precursor layer, anotherknown technique, such as, a dipping method, a spray coat method, an inkjet method or the like can be used, besides the aforementioned spin coatmethod.

Then, the substrate is heated by using, for example, a hot plate or thelike, thereby removing the solvent. Then the resin precursor layer isimidized in the furnace at about 350° C., such that the embeddinginsulation layer 106 that is almost completely set is formed. Next, asshown in FIG. 10, the upper surface of the columnar section 130 isexposed. As a method for exposing the upper surface of the columnarsection 130, a CMP method, dry etching method, wet etching method or thelike can be used.

(3) Next, forming a first electrode 107 and a second electrode 109 toinject an electric current into the active layer 103, and an emissionsurface 108 of laser light (see FIG. 1) are described.

Prior to forming the first electrode 107 and the second electrode 109,an exposed upper surface of the columnar section 130 and an exposedlower surface of the semiconductor substrate 101 may be washed by usinga plasma treatment method, or the like, depending on the requirements.As a result, a device of more stable characteristics can be formed.Then, for example, a multilayer film of Au and an alloy of Au and Zn, isformed by, for example, a vacuum deposition method on the upper surfaceof the embedding insulation layer 106 and the columnar section 130, andthen a portion where the multilayer film is not formed is formed on theupper surface of the columnar section 130 by a lift-off method. Thisportion becomes an emission surface 108. It is noted that, in the abovestep, a dry etching method or a wet etching method can be used insteadof the lift-off method.

Also, a multilayer film of Au and an alloy of Au and Ge, for example, isformed by, for example, a vacuum deposition method on the lower surfaceof the semiconductor substrate 101 which is exposed. Next, an annealingtreatment is conducted. The temperature of the annealing treatmentdepends on the electrode material. This is usually conducted at about400° C. for the electrode material used in the present exemplaryembodiment. By the steps described above, the first electrode 107 andthe second electrode 109 are formed.

By the process described above, the surface-emitting type semiconductorlaser 100 shown in FIG. 1 can be obtained.

According to the example in the step (1) described above, when growingthe second mirror 104, an AlAs layer or an AlGaAs layer that is lateroxidized and becomes the current aperture layers 20 and 22 is formed.However, a surface-emitting type semiconductor laser 100 in which thecolumnar section 130 does not include a current aperture layer, as shownin FIG. 6, may be obtained by not forming the AlAs layer or AlGaAslayer.

1-4. Functions and Effect

Main functions and effect of the surface-emitting type semiconductorlaser 100 in accordance with the present exemplary embodiment aredescribed below.

In the surface-emitting type semiconductor laser 100 of the presentexemplary embodiment, the vertical resonator 140 has a plurality of unitresonators 10 and 12, and each of the emission regions 10 a and 12 a ofthe respective unit resonators 10 and 12 has a diameter that oscillatesin a single-mode. Further, the unit resonators 10 and 12 are continuouswith one another, and the planar configuration of the vertical resonator140 has anisotropy. Since each of the unit resonators 10 and 12oscillates in a single-mode, its polarization direction is in onedirection. Due to the fact that the unit resonators 10 and 12 arecontinuous, and the planar configuration of the vertical resonator 140has anisotropy, the polarization directions of laser light of the unitresonators 10 and 12 can be aligned according to the anisotropy of theplanar configuration of the vertical resonator 140. For this reason, thepolarization directions of laser light emitted are aligned. In otherwords, in accordance with the surface-emitting type semiconductor laser100 of the present exemplary embodiment, the polarization direction oflaser light to be emitted can be controlled.

Also, according to the surface-emitting type semiconductor laser 100 inaccordance with the present exemplary embodiment, either in single-modeoscillation or multimode oscillation of laser light, the emissionpattern can be formed into an optional shape by controlling the planarconfiguration, number and arrangement of unit emission regions. For thisreason, the present exemplary embodiment can be extensively employed inlight sources of laser printers, sensors and the like.

2. Second Exemplary Embodiment

2-1 Device Structure

FIG. 11 is a schematic of a surface emitting laser 200 in accordancewith a second exemplary embodiment of the present invention. FIG.12-FIG. 14 are schematics show cross-sectional views of thesurface-emitting laser 200 taken along planes A-A, lines B-B and linesC-C in FIG. 11, respectively. FIG. 15 is a schematic of major portionsof the surface-emitting laser 200 in accordance with the secondexemplary embodiment. The same reference numerals are appended tocomponents that have substantially the same functions as those of thesurface-emitting laser 100 in accordance with the first exemplaryembodiment, and their detailed description is omitted.

As shown in FIG. 11-FIG. 14, the surface-emitting laser 200 of thepresent exemplary embodiment includes a semiconductor substrate (a GaAssubstrate in the present exemplary embodiment) 101, a vertical resonator140 formed on the semiconductor substrate 101, a first electrode 107,and a second electrode 109. The vertical resonator 140 includes a firstmirror 102, an active layer 103, and a second mirror 104.

Next, components of the surface-emitting laser 200 are described below.

The vertical resonator 140 of the present exemplary embodiment has aplurality (four in the example shown in FIG. 11) of unit resonators 10,12, 14 and 16. Each of the unit resonators 10, 12, 14 and 16 functionsas an independent resonator. Each of the unit resonators 10, 12, 14 and16 can emit its own inherent laser light.

Specifically, as shown in FIG. 11, the vertical resonator 140 is formedfrom a first unit resonator 10, a second unit resonator 12, a third unitresonator 14, and a fourth unit resonator 16. The planar configurationof each of the unit resonators 10, 12, 14 and 16 has anisotropy. In theexample shown in FIG. 11, the planar configuration of each of the unitresonators 10, 12, 14 and 16 is formed to be rectangular having longsides in the longitudinal direction (Y-direction in FIG. 11), and eachof the unit resonators 10, 12, 14 and 16 has anisotropy in the Y-axisdirection.

The vertical resonator 140 has a plurality (nine in the example of FIG.11) of aperture sections 30. The planar configuration of the aperturesection 30 is circular, for example, as shown in FIG. 11. The planarconfiguration of each of the aperture sections 30 of each of the unitresonators 10, 12, 14 and 16 is divided by borders of the unitresonators 10, 12, 14 and 16, and for example, is a ¼ circle in theexample of FIG. 11. Further, each of the unit resonators 10, 12, 14 and16 has four aperture sections 30 each in the form of a ¼ circle at thefour corners of its rectangular configuration, as viewed in a plan view.The aperture sections are embedded with embedding insulation layers 32.The embedding insulation layers 32 can be composed of, for example,polyimide resin. It is noted that although the shape of each aperturesection 30 in a region of each of the unit resonators 10, 12, 14 and 16is in the form of a ¼ circle, but the planar configuration of theaperture section 30 is circular when the concept of the unit resonators10, 12, 14 and 16 is disregarded.

In accordance with the present exemplary embodiment, a first unitcurrent aperture layer 20 is formed in a region near the active layer103 among layers composing the first unit resonator 10. A second unitcurrent aperture layer 22 is formed in a region near the active layer103 among layers composing the second unit resonator 12. A third unitcurrent aperture layer 24 is formed in a region near the active layer103 among layers composing the third unit resonator 14. Also, a fourthunit current aperture layer 26 is formed in a region near the activelayer 103 among layers composing the fourth unit resonator 16.

The first unit current aperture layer 20 has an X-Y cross section in ashape that conforms to a part of the circumference of the first unitresonator 10. The second unit current aperture layer 22 has an X-Y crosssection in the shape that conforms to a part of the circumference of thesecond unit resonator 12. The third unit current aperture layer 24 hasan X-Y cross section in the shape that conforms to a part of thecircumference of the third unit resonator 14. The fourth unit currentaperture layer 26 has an X-Y cross section in the shape that conforms toa part of the circumference of the fourth unit resonator 16. In otherwords, each of the first through fourth unit current aperture layers 20,22, 24 and 26 has a cross section, when cut in a plane parallel with theX-Y plane in FIG. 12 or FIG. 13, in the shape that is a quarter of aring shape concentric with the aperture section 30 described above. Thefirst through fourth unit current aperture layers 20, 22, 24 and 26 maybe composed of aluminum oxide, for example. It is noted that, althougheach of the first through fourth unit current aperture layers 20, 22, 24and 26 is in the form of a quartered ring shape, the planarconfiguration of each of the current aperture layers is a ring shapewhen the concept of the unit resonators 10, 12, 14 and 16 isdisregarded.

The above is more concretely described with reference to FIG. 15 thatshows an enlarged view of only the unit resonator 10. The planarconfiguration of the unit resonator 10 is a rectangle, and the embeddinginsulation layer 32 is arranged on the four corners thereof. The planarconfiguration of the embedding dielectric layer 32 is a ¼ circle. Theunit current aperture layer 20 is formed around the embedding insulationlayer 32. The unit current aperture layer 20 is formed from fourinsulation layers 21 a, 21 b, 21 c, and 21 d. The planar configurationof each of the four insulation layers 21 a, 21 b, 21 c, and 21 d has a ¼ring shape that is concentric with the embedding insulation layer 32.Outer circular arcs of these four insulation layers 21 a, 21 b, 21 c,and 21 d define an external shape of an opening section 20 a of the unitcurrent aperture layer 20. The opening section 20 a defines an emissionregion 10 a of the unit resonator 10.

Each of the emission regions 10 a, 12 a, 14 a and 16 a of the respectiveunit resonators 10, 12, 14 and 16 has a size that oscillates in asingle-mode. The size of each of the emission regions 10 a, 12 a, 14 a,and 16 a is defined by each of the opening sections 20 a, 22 a, 24 a and26 a of the respective unit current aperture layers 20, 22, 24 and 26.For example, in the example shown in FIG. 11, the size of the emissionregion 10 a of the first unit resonator 10 corresponds to the size ofthe opening section 20 a of the first unit current aperture layer 20,the size of the emission region 12 a of the second unit resonator 12corresponds to the size of the opening section 22 a of the second unitcurrent aperture layer 22, the size of the emission region 14 a of thethird unit resonator 14 corresponds to the size of the opening section24 a of the third unit current aperture layer 24, and the size of theemission region 16 a of the fourth unit resonator 16 corresponds to thesize of the opening section 26 a of the fourth unit current aperturelayer 26. The size of the opening section 20 a can be, for example, thelength of a line segment a indicated by an arrow in FIG. 15. The lengthof the line segment a can be, for example, the length of each side of asquare b that circumscribes the ¼ circles that define the planarconfiguration of the four insulation layers 21 a, 21 b, 21 c, and 21 d.This similarly applies to the diameter of the other openings 22 a, 24 a,and 26 a. The size that oscillates in a single-mode is properly decidedby the position and thickness of each of the unit current aperturelayers 20, 22, 24 and 26, the wavelength, etc., and may be 4-4 m orless, for example.

An impurity layer 40 is formed around the vertical resonator 140 in thesecond mirror 104. This impurity layer 40 is provided for isolatingelements. This layer reduces the likelihood or prevents an electriccurrent injected into the vertical resonator 140 from flowing outside ofthe vertical resonator 140. For example, proton can be used for theimpurity layer 40.

An insulation layer 50 is provided on the upper surface of the secondmirror 104, and regions other than the upper surface of the verticalresonator 140. The insulation layer 50 electrically separates a firstelectrode 107 to be described later from the second mirror 104 arrangedaround the vertical resonator 140.

The first electrode 107 is formed above the circumference of thevertical resonator 140 and above the insulation layer 50. In addition, apart (opening section) where the first electrode 107 is not formed isprovided in the central part of the upper surface of the verticalresonator 140. This part is an emission region of laser light. Forexample, the first electrode 107 is composed of a multilayer film of Auand an alloy of Au and Zn. In addition, a second electrode 109 is formedon the lower surface of the semiconductor substrate 101. For example,the second electrode 109 is composed of a multilayer film of Au and analloy of Au and Ge.

The materials to form the first and second electrodes 107 and 109 arenot limited to those described above, and, for instance, metals, such asCr, Ti, Ni, Au or Pt and these alloys, etc. can be used depending on therequirements for adhesion enforcement, diffusion prevention oranti-oxidation, etc.

In the example shown in FIG. 11, the vertical resonator 140 has fourunit resonators 10, 12, 14 and 16. However, the vertical resonator 140can have a plurality of unit resonators.

Also, in the example shown in FIG. 11, the size of the emission regions10 a, 12 a, 14 a and 16 a of the first through fourth unit resonators10, 12, 14 and 16 have the same length. However, the emission regions ofthe unit resonators may have different sizes. For example, as shown inFIG. 16, the size of the emission regions 10 a and 12 a of the first andsecond unit resonators 10 and 12 can be formed to have lengths differentfrom the size of the emission regions 14 a and 16 a of the third andfourth unit resonators 14 and 16. When the sizes of the emission regionshave the same length, laser light emitted from the respective emissionregions have the same wavelength. However, when the sizes of theemission regions have different lengths, laser light emitted from therespective emission regions have different wavelengths. In the exampleshown in FIG. 16, the size of each of the emission regions 10 a, 12 a,14 a and 16 a is set such that the wavelength of laser light emittedfrom the first and second emission regions 10 a and 12 a is differentfrom the wavelength of laser light emitted from the third and fourthemission regions 14 a and 16 a. The reason why the wavelength of emittedlaser light is different depending on the size (larger or smaller) ofeach emission region is that the electric resistance differs dependingon the size of the emission region. Specifically, because the smallerthe size of the emission region, the greater the electric resistance andthe greater the heat generated therefrom, compared to an emission regionhaving a larger size, the laser light shifts to the long-wavelengthside, and the two emit laser light having different wavelengths.

2-2 Operation of Device

General operations of the surface-emitting type semiconductor laser 200of the present exemplary embodiment are described below. It is notedthat the following method for driving the surface-emitting typesemiconductor laser 200 is described as an example, and various changescan be made without departing from the subject matter of the presentinvention. Details of operations that are substantially the same asthose of the first exemplary embodiment are omitted.

The vertical resonator 140 of the surface-emitting type semiconductorlaser 200 in accordance with the present exemplary embodiment has aplurality of unit resonators 10, 12, 14 and 16. Each of the emissionregions 10 a, 12 a, 14 a and 16 a of the unit resonators 10, 12, 14 and16 has a size that oscillates in a single-mode. Also, the planarconfiguration of each of the unit resonators 10, 12, 14 and 16 hasanisotropy. Since each of the unit resonators 10, 12, 14 and 16oscillates in a single-mode, its polarization direction is in onedirection. Because the planar configuration of each of the unitresonators 10, 12, 14 and 16 has anisotropy, the polarization directionsof laser light of the unit resonators 10, 12, 14 and 16 can be alignedaccording to the anisotropy of the planar configuration of the unitresonators 10, 12, 14 and 16. For this reason, the polarizationdirections of laser light emitted are aligned. The laser light isemitted with its polarization direction controlled. Specifically, thepolarization directions are aligned in the minor axis direction. In theexample shown in FIG. 11, for example, the polarization directions arealigned in the X-direction.

In the surface-emitting type semiconductor laser 200 in accordance withthe present exemplary embodiment, as shown in FIG. 11, when the unitresonators 10, 12, 14 and 16 have the same size, laser light generatedby the unit resonators 10, 12, 14 and 16, have the same wavelength,resulting in oscillation in a single-mode as a whole. When the first andsecond unit resonators 10 and 12 and the third and fourth unitresonators 14 and 16, have different sizes, as shown in FIG. 16, laserlight generated by the first and second unit resonators 10 and 12 andlaser light generated by the third and fourth unit resonators 14 and 16have different wavelengths, resulting in oscillation in a multimode as awhole.

2-3 Device Manufacturing Method

Next, an example of a method of manufacturing the surface-emitting typesemiconductor laser 200 in accordance with a second exemplary embodimentof the present invention will be described with reference to FIG. 17through FIG. 24. FIG. 17, FIG. 19, FIG. 21 and FIG. 23 are schematicsshowing the method of manufacturing the surface-emitting typesemiconductor laser 200 according to the present exemplary embodimentshown in FIG. 11 through FIG. 14. FIG. 18, FIG. 20, FIG. 22 and FIG. 24are cross-sectional schematics showing the method of manufacturing thesurface-emitting type semiconductor laser 200 according to the presentexemplary embodiment shown in FIG. 11 through FIG. 14, each of whichcorresponds to the cross section shown in FIG. 12. Detailed descriptionsof steps that are substantially the same as those of the first exemplaryembodiment are omitted.

(1) First, on the surface of the semiconductor substrate 101 composed ofn-type GaAs, a semiconductor multilayer film 150, shown in FIG. 18, isformed by epitaxial growth while modifying its composition. It is notedhere that the semiconductor multilayer film 150 is formed from a firstmirror 102, an active layer 103 and a second mirror 104.

When growing the second mirror 104, at least one layer thereof adjacentto the active layer 103 is formed as an AlAs layer or an AlGaAs layerthat is later oxidized and becomes current aperture layers 20, 22, 24and 26 (see FIG. 11).

Then, resist is coated on the semiconductor multilayer film 150. Thenthe resist is patterned by a photolithography method, thereby forming afirst mask layer R100 having a specified pattern, as shown in FIG. 17and FIG. 18. The first mask layer R100 is formed over the second mirror104 except regions where aperture sections 30 (see FIG. 11) are to beformed. Specifically, the aperture sections 30 are disposed atintersections of longitudinal and transverse lines that compose alattice shape. For example, in the example of FIG. 11, the longitudinaldirection is the Y-direction, and transverse direction is theX-direction. Pitch widths of the longitudinal and transverse lines ofthe lattice shape can be different from one another. For example, in theexample of FIG. 11, the pitch width in the Y-direction is greater thanthe pitch width in the X-direction. In the example of FIG. 11, the pitchwidths in the X-direction are the same, and the pitch widths in theY-direction are the same. However, the pitch widths in the X-directioncan be different from one another, and the pitch widths in theY-direction can be different from one another.

Next, by using the first mask layer R100 as a mask, at least the secondmirror 104 is etched by, for example, a dry etching method, therebyforming the aperture sections 30, as shown in FIG. 17 and FIG. 18. Then,the first mask layer R100 is removed.

Next, by placing the semiconductor substrate 101 in a water vaporatmosphere at about 400° C., for example, the layer having a high Alcomposition (a layer with an Al composition being 0.95 or higher) amongthe second mirror 104 is oxidized from its side surface through theaperture sections 30, thereby forming the current aperture layers 20,22, 24 and 26, as shown in FIG. 19 and FIG. 20. The oxidation ratedepends on the temperature of the furnace, the amount of water vaporsupply, and the Al composition and the film thickness of the layer to beoxidized. Then, the apertures 30 are embedded with embedding insulationlayers 32.

(2) Next, an impurity layer 40 that surrounds the vertical resonator 140is formed, as shown in FIG. 21 and FIG. 22. The impurity layer 40 can beformed by forming a mask layer by using an ordinary lithographytechnique, and injecting prescribed impurities into the second mirror104.

(3) Next, an insulation layer 50 is formed on the upper surface of thesecond mirror 104, and in regions other than on the vertical resonator140, as shown in FIG. 23 and FIG. 24. For example, the insulation layer50 can be formed by a CVD method, or the like. For example, siliconoxide, silicon nitride or polyimide can be used for the insulation layer50.

(4) Next, a process of forming a first electrode 107 and a secondelectrode 109 for injecting an electric current into the active layer103 is described.

First, for example, a multilayer film of Au and an alloy of Au and Zn isformed by, for example, a vapor deposition method over the upper surfaceof the circumference of the vertical resonator 140 and on the uppersurface of the insulation layer 50. Then, a part where theabove-mentioned multilayer film is not formed is formed by a lift-offmethod on the upper surface of the vertical resonator 140. This partbecomes an emission surface of laser light. A dry etching method or awet etching method can be used in the above-mentioned step instead ofthe lift-off method.

Also, a multilayer film of Au and an alloy of Au and Ge, for example, isformed by, for example, a vacuum deposition method on the lower surfaceof the semiconductor substrate 101 which is exposed. Next, an annealingtreatment is conducted. By the steps described above, the firstelectrode 107 and the second electrode 109 are formed.

By the process described above, the surface-emitting type semiconductorlaser 200 shown in FIG. 11 and FIG. 14 can be obtained.

2-4. Functions and Effect

Main functions and effect of the surface-emitting type semiconductorlaser 200 in accordance with the present exemplary embodiment aredescribed below.

In the surface-emitting type semiconductor laser 200 of the presentexemplary embodiment, the vertical resonator 140 has a plurality of unitresonators 10, 12, 14 and 16. Each of the emission regions 10 a, 12 a,14 a and 16 a of the respective unit resonators 10, 12, 14 and 16 has asize that oscillates in a single-mode. Also, each of the unit resonators10, 12, 14 and 16 has anisotropy. Since each of the unit resonators 10,12, 14 and 16 oscillates in a single-mode, its polarization direction isin one direction. Because the planar configuration of each of the unitresonators 10, 12, 14 and 16 has anisotropy, the polarization directionsof laser light of the unit resonators 10, 12, 14 and 16 can be alignedaccording to the anisotropy of the planar configuration of the unitresonators 10, 12, 14 and 16. For this reason, the polarizationdirections of laser light emitted are aligned. In other words, inaccordance with the surface-emitting type semiconductor laser 200 of thepresent exemplary embodiment, the polarization direction of laser lightto be emitted can be controlled.

Also, according to the surface-emitting type semiconductor laser 200 inaccordance with the present exemplary embodiment, either in single-modeoscillation or multimode oscillation of laser light, the emissionpattern can be formed into an optional shape by controlling the planarconfiguration, number and arrangement of unit emission regions. For thisreason, the present exemplary embodiment can be extensively employed inlight sources of laser printers, sensors and the like.

Although exemplary embodiments of the present invention are describedabove, the present invention is not limited to these embodiments, andmany modifications can be made within the scope of the subject matter.In the exemplary embodiments described above, the description was madeas to a two-face electrode structure in which the first electrode 107 isformed on the upper surface of the second mirror 104, and the secondelectrode 109 is formed on the lower surface of the semiconductorsubstrate 101. However, a one-face electrode structure in which thefirst electrode 107 is formed on the upper surface of the second mirror104 and the second electrode 109 is formed on the upper surface of thefirst mirror 102 can also be made.

In the above described exemplary embodiments, the description is made asto an AlGaAs type surface-emitting laser, but the present invention isalso applicable to other types of surface-emitting lasers, such as, forexample, GaInP type, ZnSSe type, InGaN type, AlGaN type, InGaAs type,GaInNAs type, GaAsSb type, and like.

1. A surface-emitting type semiconductor laser, comprising: a substrate;a vertical resonator above the substrate, the vertical resonatorincluding a first mirror, an active layer and a second mirror disposedin this order from the substrate, and a plurality of unit resonators, anemission region of each of the plurality of unit resonators having adiameter that oscillates in a single-mode.
 2. The surface-emitting typesemiconductor laser according to claim 1, the vertical resonator furtherincluding a unit current aperture layer formed along at least a part ofa circumference of the plurality of unit resonators, and a diameter ofthe emission region being defined by an opening section of the unitcurrent aperture layer.
 3. The surface-emitting type semiconductor laseraccording to claim 1, the plurality of unit resonators being continuouswith each other, and a planar configuration of the vertical resonatorhaving anisotropy.
 4. The surface-emitting type semiconductor laseraccording to claim 3, the plurality of unit resonators being continuousthrough a continuation region.
 5. The surface-emitting typesemiconductor laser according to claim 2, the opening section of theunit current aperture layer of the plurality of unit resonators beingcontinuous.
 6. The surface-emitting type semiconductor laser accordingto claim 1, a planar configuration of each of the unit resonators havinganisotropy.
 7. The surface-emitting type semiconductor laser accordingto claim 1, each of the plurality of unit resonators having an identicaldiameter, and laser light of each of the unit resonators has anidentical wavelength.
 8. The surface-emitting type semiconductor laseraccording to claim 7, the surface-emitting type semiconductor laseroscillating in a single-mode as a whole.
 9. The surface-emitting typesemiconductor laser according to claim 1, the plurality of unitresonators having at least two different diameters, and laser light ofthe plurality of respective unit resonators having at least twodifferent wavelengths.
 10. The surface-emitting type semiconductor laseraccording to claim 9, the surface-emitting type semiconductor laseroscillating in a multimode as a whole.
 11. The surface-emitting typesemiconductor laser according to claim 9, the wavelength of laser lightemitted from the emission region with a smaller diameter is longer thanthe wavelength of laser light emitted from the emission region with alarger diameter
 12. The surface-emitting type semiconductor laseraccording to claim 2, the vertical resonator having an aperture sectionthat reaches at least the unit current aperture layer.
 13. Thesurface-emitting type semiconductor laser according to claim 12, theaperture section being embedded with insulation material.
 14. A methodfor manufacturing a surface-emitting type semiconductor laser having avertical resonator above a substrate, comprising: stacking semiconductorlayers to form at least a first mirror, an active layer and a secondmirror over the substrate; and forming a vertical resonator having acolumnar section by etching the semiconductor layers by using a masklayer, the vertical resonator being formed to have a plurality of unitresonators, and an emission region of each of the plurality of unitresonators being formed to have a diameter that oscillates in asingle-mode.
 15. The method for manufacturing a surface-emitting typesemiconductor laser according to claim 14, further comprising: forming aunit current aperture layer along at least a part of a circumference ofthe unit resonators.
 16. A method for manufacturing a surface-emittingtype semiconductor laser having a vertical resonator above a substrate,comprising: stacking semiconductor layers to form at least a firstmirror, an active layer and a second mirror over the substrate; formingaperture sections by etching the semiconductor layers; and formingcurrent aperture layers near the active layer by oxidizing a part of thesemiconductor layers through the aperture section; forming the verticalresonator to have a plurality of unit resonators, forming an emissionregion of each of the unit resonators to have a diameter that oscillatesin a single-mode, and forming the current aperture layer along at leasta part of a circumference of each of the unit resonators.
 17. The methodfor manufacturing a surface-emitting type semiconductor laser accordingto claim 16, the aperture sections being disposed at intersections oflongitudinal and transverse lines composing a lattice shape, andlongitudinal and transverse pitch widths of the lattice shape beingdifferent from one another.